Axitinib (AG-013736) is a potent investigational drug that has antitumor activity in patients with metastatic renal cell carcinoma and other types of cancers. In this study, ion mobility spectrometry and “direct analysis in real time”� (DART®™) mass spectrometry were used to rapidly identify AG-013736 in drug substance samples and 1 mg Axitinib tablets. The plasmagrams of the sample solutions exhibited a major peak with a reduced ion mobility that was within ±0.0002 cm2 V?1 s?1 of that for AG-013736 in an external reference standard solution. The DART® ionization source was coupled with both a time-of-flight mass spectrometer and a lower-resolution ion trap mass spectrometer. Samples were analyzed by this technique in as little as 5 s with minimal to no sample preparation required. The isotopic masses of the protonated dimer ions of AG-013736 were used to identify AG-013736 in the active tablet. Both techniques were also used to develop low-level limit tests for rapidly verifying the presence or absence of AG-013736 in blinded clinical supplies of active and matching placebo tablets of Axitinib.